(1) Field of the Invention
The present invention relates to O-ring insertion tools and methods and more particularly, to a tool and method for inserting an oversized O-ring into a standard or O-ring groove in an O-ring housing.
(2) Description of the Prior Art
O-rings are commonly used to accomplish sealing in various types of housings to prevent the passage of liquids or gasses therethrough. Positioning the O-ring has been a problem especially in housings where the O-ring is seated in an internal O-ring groove within the housing. New O-ring seal designs have made insertion of the O-ring even more difficult.
In one example, a dual O-ring seal system has been designed to provide a high pressure seal for a propulsor rotary shaft in a torpedo. This high pressure dual O-ring seal system requires oversized O-rings to be installed within an inner floating seal housing. Although this can be accomplished by hand, installation by hand is difficult if the O-ring is hard, slippery and considerably oversized.
Canted O-rings further complicate installation. In a canted O-ring design, the O-ring is provided at an angle in a plane not perpendicular to the axis of the shaft in order to provide for better lubrication and reduced wear.
One object of the present invention is facilitating insertion of an oversized O-ring into an O-ring groove within an O-ring housing.
Another object of the present invention is aiding insertion of one or more O-rings into a canted O-ring groove within an O-ring housing.
To accomplish these objectives, the present invention features an insertion tool comprising a base having a top base surface for supporting the O-ring housing. An O-ring support extends from the top base surface and is supported on the top base surface and around the O-ring support. The O-ring support has a top surface that generally aligns with the O-ring groove in the O-ring housing. In one embodiment, the O-ring support is wedge shaped and the top support surface is angled with respect to the top base surface such that the top support surface generally aligns with a canted O-ring groove in the O-ring housing. A hole extends through the base and the O-ring support and is generally perpendicular to the top support surface.
Four to eight segments are positioned on the top support surface for securing respective sections of the O-ring into the O-ring groove in the O-ring housing. A plurality of spaces are formed between adjacent ones of the plurality of segments. A plurality of radial pushers are positioned on the top support surface and are received in respective spaces between the segments. Each of the radial pushers includes a cam surface facing a center of the O-ring support. A retainer is positioned onto the segments and the radial pushers to retain the segments and pushers on the top support surface.
The insertion tool also comprises a central pusher having a rod and a cam plunger at one end of the rod. The rod extends through the hole in the O-ring support and the base such that the cam plunger engages the cam surface on each of the pushers and causes the pushers to push the O-ring loops into the O-ring groove.
In the preferred embodiment, the insertion tool further includes a plurality of O-ring holding pins slidingly extending through the base and through the O-ring support. O-ring loops are formed around each of the O-ring holding pins and within the spaces between the segments. A retractor, coupled to the O-ring holding pins, retracts the O-ring holding pins all at once below the top support surface before the radial pushers push the O-ring loops into the O-ring groove. Segment holding pins preferably extend from the top support surface into each of the segments for holding the segments into position on the top support surface.
According to one embodiment, the retainer is ring shaped, and the segments are pie shaped. Where the O-ring is being inserted into a canted O-ring groove, the segments and the retainer have elliptical mating edge surfaces corresponding to the canted O-ring groove when positioned on the angled top support surface of the O-ring support.